A vision is presented for a fully IP-based mobile network which goes beyond UMTS/IMT-2000. A top-to-bottom design approach is introduced that is capable of offering new and innovative services and applications to both fixed and mobile users efficiently, cost effectively and in a user-friendly manner. Some issues and examples in the design steps following this new approach are discussed. It is clearly shown that the convergence of mobile and fixed networks will be achieved naturally through the use of an `all IP' based solution for both access and core networks.